Spinal fusion surgical procedures involve joining or fusing two or more vertebrae together. The procedure typically includes using bone graft or bone growth material to promote fusion. The bone material and a spinal implant (also known as a spacer or cage) are inserted in the intervertebral space and take the place of an intervertebral disc. The spacer bears the load transferred from one vertebra to the next vertebra, and in conjunction with the bone graft material, acts to fuse the vertebrae together. Spinal fusion surgery can be used to treat spinal fractures, lumbar disc herniation, scoliosis, and other spinal disorders.
Several procedures are known for implanting spinal implants. The posterior lumbar interbody fusion (“PLIF”) procedure involves making an incision in the patient's back and retracting the spinal muscles to allow access to the vertebral space. Next, the lamina is removed to allow visualization and access to the nerve roots. The affected intervertebral disc is removed and the space prepared for the implant. The bone graft or bone growth material and the spinal implant are inserted into the disc space to promote fusion. The transforaminal lumbar interbody fusion (“TLIF”) procedure is a modification of the PLIF procedure. During the TLIF procedure, the incision is made to the side of the spinal canal through a midline incision in the patient's back. This reduces the amount of muscle retraction and nerve manipulation required. In the anterior lumbar interbody fusion (“ALIF”) procedure, the incision is made in the lower abdominal area. This procedure may involve cutting through the lower abdominal muscles.
A number of spinal implants are known in the art. However, there is a need for an improved spinal fusion spacer that facilitates improved packing of bone material or bone growth promoter in and around the spacer in the disc space while minimizing the invasiveness of the implantation procedure.